ff_formats_changeref

Before After ________ ________ |formats |<---------. |formats |<---------. | ____ | ___|___ | ____ | ___|___ | |refs| | | | | | |refs| | | | | NULL | |* *--------->|*oldref| | |* *--------->|*newref| ^ | |* * | | |_______| | |* * | | |_______| ___|___ | |____| | | |____| | | | | |________| |________| |*oldref| |_______|